1. Field of the Invention
Aspects of the present invention relate to a computer system and a control method thereof, and more particularly, to a computer system with a plurality of ports to which external devices are mounted and from which the external devices can draw electric power, and a control method thereof.
2. Description of the Related Art
A computer system (such as a desktop computer, a laptop computer, or the like) includes various ports for interfaces with internal or external devices. As a representative example of the ports, there is a universal serial bus (USB) port. FIG. 1 is a block diagram of a conventional computer system 10 with a USB port. The computer system 10 includes a central processing unit 11, an input/output control hub (ICH) 13 for input/output control of peripheral units, and a memory control hub (MCH) 12 for memory control. Further, the computer system 10 includes a plurality of USB ports 14 and 15, to which a corresponding external device 21 is mounted according to a USB standard.
Each of the USB ports 14 and 15 is connected to a power source Vcc of 5V so that the external device 21 can draw electric power therefrom. Specifically, as shown in FIG. 1, power terminals PWR1 and PWR2 of the USB ports 14 and 15 are connected to power supplying lines 17 and 18 branched from the power source Vcc, respectively. The computer system 10 includes a power switch 16 to cut off an overcurrent when the overcurrent flows in the power supplying lines 17 and 18, thereby preventing element damage, fire, etc.
Meanwhile, the USB specification, such as USB Specification 2.0, describes that the USB ports 14 and 15 each is provided with a direct current (DC) power of 5V and a current of 500 mA. Thus, the computer system 10 has a power configuration designed in consideration of this specification.
However, an external device 21 that needs an electric power of 500 mA or more has recently come out as the performance thereof is enhanced or for the like reasons. In this case, if the power supplying lines 17 and 18 are not designed to supply the electric power proper for the external device 21, the external device 21 may abnormally operate due to supply of insufficient electric power.
To solve this problem, there have been considered methods in which intensity of suppliable current increased per power supplying line, an additional power source is connected to the port, etc. However, these methods increase the costs of the power configuration. Further, if the connection of the additional power source depends on manipulation of a user, it brings inconvenience to a user. Also, a user may not make good use of the additional power source for lack of adequate understanding.